1. Field of the Invention
The present invention relates to a night vision system, and more particularly to an improved night vision system usable as either a helmet mounted or face mask mounted monocular, or as a pocketscope.
2. Description of Related Art
Night vision systems are commonly used by military and law enforcement personnel for conducting operations in low light or night conditions. Night vision systems are also used to assist pilots of helicopters or airplanes in flying at night. Such night vision systems either take the form of binoculars, having separate eyepieces for each eye, or monoculars, having only a single eyepiece.
A night vision system intensifies the ambient light to produce an image. These systems require some residual light, such as moon or starlight, in which to operate. The ambient light is intensified by the night vision scope to produce an output image which is visible to the human eye. The present generation of night vision scopes utilize image intensification technologies to intensify the low level of visible light and also make visible the light from the infra-red (IR) spectrum. The image intensification process involves conversion of the received ambient light into electron patterns and projection of the electron patterns onto a phosphor screen for conversion of the electron patterns into light visible to the observer. This visible light is then viewed by the operator through a lens provided in the eyepiece of the system.
The typical night vision system has an optics portion and a control portion. The optics portion comprises lenses for focusing on the desired target, and an image intensifier tube. The image intensifier tube performs the image intensification process described above. The control portion comprises the electronic circuitry necessary for controlling and powering the optical portion of the night vision system. Although technologically advanced, all of the prior art systems fail to meet one or more of the human factors requirements of the typical operator.
For example, the typical control portions take up considerable space in comparison to the optical portion. To be most effective, a night vision system must be small, rugged and lightweight. While binocular systems have the advantage of allowing the operator to determine depth of field, binocular systems are often bulkier and heavier. Although monocular systems are smaller, the control portions are often as large as the optical portion. This makes the device cumbersome to manipulate.
Monocular systems are additionally advantageous since it is often desirable for the operator to have a single eye not coupled to the night vision system, or "free". This free eye can remain adapted to the darkness, so that if the night vision system is disengaged the operator will not be temporarily blinded as his iris dilates to adapt for the night conditions. The operator may also wish to keep one eye free in order to aim a weapon, since it is also common for weapons to be equipped with an eyepiece for sighting purposes. These eyepieces frequently utilize a night vision system as well. An operator may utilize a monocular system with a first eye, in conjunction with a night vision system equipped on a weapon for use by the other eye. Thus, monocular systems are frequently preferred over binocular systems.
It is common for operators to use a night vision system as a pocketscope. When not in use, the pocketscope can be conveniently stowed in a pocket or backpack, or can be attached to a lanyard and hung from the operator's neck. When needed, the operator would hold the pocketscope up to his eye to observe the night environment. To be most effective, a pocketscope must be small, lightweight and easy to manipulate.
If an operator desires hands free operation, binocular and monocular systems are frequently mounted to a mask worn on the operator's face. The typical face mask mounting assembly comprises a bar or rod having a plurality of cushion plates attached thereto. The bar would partially encircle the operator's face, and the cushion plates would press against specific points on the face, such as the cheeks and the forehead. The bar is held to the face by use of a strap which wraps around the head and connects to the bar at two places. At the forehead portion of the bar, a mount is provided which would attach to the binocular or monocular system. As discussed below, this mounting method has significant disadvantages.
If the operator is wearing a monocular system, it is often necessary to switch the monocular from eye to eye. To accommodate this, face masks either utilize a pair of mounting points, or a pivoting system in which the monocular is pivoted from the left eye position to the right eye position. A significant problem with this configuration is that it is time consuming to move the monocular from one eye to the next. The monocular must be readjusted in the new position to accommodate the precise position of the operator's eye. While the time required to make the configuration change and adjustment may be slight, it could mean the difference between life and death of an operator.
Another type of prior art face mask has a horizontal bar mounted to the front of the face mask above the operator's eyes, to which a night vision monocular is attached. A locking screw holds the monocular in a position on the bar. The operator slides the monocular along the bar to move it from proximity with one eye to the second eye. This presents a problem to the operator, since each time the position of the monocular is changed, the operator must carefully calibrate the new position with his eye to effectively use the monocular.
Another problem with face mask mounting is that the adjustments of the mask could be altered by the wearing of a helmet. If an operator intends to wear a standard ballistic helmet, the mask must be first adjusted to the operator's face prior to putting the helmet on. The operator adjusts the mask for alignment of the scope with the eyes and tightens the mask so that it remains in the adjusted position. When the helmet is put on the operator's head, the bulk and weight of the helmet frequently interferes with the upper portion of the face mask. This forces the mask downward relative the operator's face knocking the monocular or binocular out of alignment with the operator's eyes. The operator must then readjust the mask to accommodate the weight and bulk of the helmet. Alternatively, the operator can readjust the helmet so that it rides higher on the head, and does not interfere with the mask. However, this usage of the helmet is dangerous for the operator, since it removes the temples, forehead and back of the head from protection by the helmet.
Since conditions often occur in which there is extremely little ambient light, it is common for night vision systems to also include a small infra-red radiation source. The radiation source can be energized by the operator to illuminate the local area with a cone of infra-red light which, although invisible to the unaided eye, can be seen by the observer through the eyepiece of the night vision system. Frequently, operators mistakenly leave the infra-red source powered on, without realizing it. This poses a significant danger to the operator, since hostile forces equipped with night vision systems can also see the radiation source.
The prior art devices provide a mechanism for insuring that the operator knows the infra-red source is activated. The switch which activates the source must be simultaneously turned and pushed. The additional step of pushing requires an intentional act by the operator, so that the source could not be activated by accident. However, once the source is activated, the switch remains in the activated position. Since the operator does not receive any additional notification that the infra-red source is activated, the operator could forget to de-activate the source, and be seen by hostile forces.
Most night vision systems utilize an internal battery which provides electrical power to the image intensification tube and the radiation source. These battery powered systems can only run for a finite period of time before the battery must be replaced. Once the battery has run down, the night vision system is rendered useless. None of the prior art night vision systems provide a mechanism visible within the eyepiece for warning the operator that the battery is running low and should be replaced.
Thus, it would be desirable to provide a human engineered night vision system with a compact control section, so that it could be easily manipulated by an operator as a pocketscope for hand held operations. It would be further desirable to provide a night vision monocular which could be easily and rapidly switched between an operator's eyes. It would be further desirable to provide a mounting system for a monocular or binocular to be used in conjunction with the wearing of a helmet, or in association with a face mask. It would also be desirable to provide a night vision monocular with an IR illumination system which would allow an operator to only permit a burst of IR light to be illuminated from the system. It would also be desirable to provide a night vision monocular having a mechanism that more reliably informs the operator that the IR illumination system is in use. It would be still further desirable to provide a night vision system having a mechanism that reliably informs the operator that the internal battery is running low.